FORT MEADE, MD, April 25 (Reuters) - Bradley Manning, theU.S. intelligence analyst charged with leaking thousands ofclassified U.S. government cables to the anti-secrecy groupWikiLeaks, called on a military court on Wednesday to dismissthe charge that he aided an enemy of the United States,identified as Al Qaeda.

Manning, 24, who faces a military trial in September, isaccused of downloading more than 700,000 classified orconfidential files from the military while serving in Iraq inwhat would be the largest leak of classified documents in U.S.history.

Military prosecutors claim Manning knowingly gave U.S.intelligence to an enemy they have identified as "Al Qaeda inthe Arabian Peninsula," one of the terrorist group's most potentaffiliates, through the "indirect means" of the site WikiLeaks.

Manning's attorney David Coombs pressed the court to dismissthe most serious of the 22 charges against Manning on the basisof what he called an overly broad interpretation of the law.

"They're really trying to say he should have known better,"Coombs said, arguing that simply providing information to bepublished on the Internet does not constitute aiding enemies ofthe United States and that the prosecution's interpretationviolates the right to free speech.

Manning wanted to get information out to the public, butnever showed "general evil intent" to give information to theenemy, Coombs said. He compared Manning's actions to a soldierspeaking to publications like the Washington Post or the NewYork Times.

Prosecutors argued Manning knowingly provided informationbased on his training as an intelligence analyst.

A soldier who, without proper authority, knowingly givesintelligence to the enemy can be punished for aiding the enemy,said a legal expert with the Military District of Washington,the Army command unit for the capital region, who was present atthe hearing.

The judge, Colonel Denise Lind, said she would rule on themotion on Thursday, the third day of pre-trial hearings.

Aiding the enemy is a capital offense but the prosecutor hassaid it would not seek the death penalty in Manning's case.Manning could, however, face life in prison.

DISMISSAL OF CHARGES DENIED

In a blow to the 24-year-old, Lind ruled against a motionfiled by Manning's lawyer to dismiss all charges because of whathe called the prosecutor's intentional withholding of evidenceneeded to prepare Manning's defense, and set a tentative trialschedule for Sept. 21 through Oct. 12.

Manning's trial will take place more than two years after hewas arrested.

"The court finds no evidence of prosecutorial misconduct,"Lind said at the pre-trial hearing.

Manning, in a dark blue military dress uniform andblack-rimmed glasses, listened intently to the arguments,occasionally leaning in to talk with his lawyer.

A handful of Manning's supporters, who view him as awhistleblower, filled the pews behind Manning wearing T-shirtswith the word "truth." Lind instructed them to hold back frommaking any noise during court proceedings after one guffawed atthe judge's ruling.

Lind also denied a defense motion for a transcript or audiofile of a grand jury in Alexandria, Virginia that has beeninvestigating WikiLeaks founder Julian Assange, but ordered thetestimony be examined for material relevant to Manning'sdefense.

Lind said that although the FBI and the Army have pursued aWikiLeaks investigation, military prosecutors did not have theauthority to release FBI documents.

Manning is accused of downloading files from the military'sSecret Internet Protocol Router Network, or SIPRNet, whileserving in the Army's 10th Mountain Division in Iraq.